Defensive publication

ABSTRACT

IN THE PROCESS FOR PRODUCING MULTILAYER CERAMIC CIRCUIT BOARDS COMPRISING LAMINATING BY FIRING TWO OR MORE LAYERS OF GREEN CERAMIC TAPE, WHEREIN ONE OR MORE SURFACES OF THE LAYERS OF TAPE HAVE ELECTRICAL COMPONENTS, PRINTED THEREON AND WHEREIN THE GREEN CERAMIC TAPE SHRINKS DIFFERENTIALLY IN ITS WIDTH OR X-AXIS DIRECTION AS COMPARED TO ITS LENGTH OR Y-AXIS DIRECTION WHEN FIRED, THE IMPROVEMENT WHICH COMPRISES MINIMIZING DIFFERENTIAL SHRINKAGE OF THE CIRCUIT BOARDS UPON FIRING BY STACKING THE LAYERS OF GREEN TAPE ALTERNATELY SO THAT EACH SUCCESSIVE LAYER HAS ITS X-AXIS DIRECTION ALIGNED WITH THE Y-AXIS DIRECTION OF THE PRECEDING LAYER. THE GREEN CERAMIC TAPE COMPRISES FINELY DIVIDED CERAMIC PARTICLES AND AN ORGANIC BINDER THEREFOR AND IS PREPARED BY DOCTOR BLADING AN AQUEOUS OR ORGANIC DISPERSION OF THE CERAMIC PARTICLES AND THE BINDER, FOLLOWED BY ELIMINATING THE SOLVENT, E.G., BY DRYING. AFTER STACKING THE LAYERS OF GREEN TAPE IN THE ABOVE-DESCRIBED ORIENTATION, THE LAYERS ARE LAMINATED, E.G., BY HEAT OR PRESSURE, AND THEN FIRED TO SINTER THE CERAMIC LAYERS AND TO REMOVE THE BINDER.

UNITED STATES PATENT OFFICE Published at the request of the applicant orowner in accordance with the Notice of Dec. 16, 1969, 869 0.G. 687. Theabstracts of Defensive Publication applications are identified bydistinctly numbered series and are arranged chronologically. The headingof each abstract indicates the number of pages of specification,including claims and sheets of drawings contained in the application asOriginally filed. The files of these applications are available to thepublic for inspection and reproduction may be purchased for 30 cents asheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent Oifice makes no assertion as tothe novelty of the disclosed subject matter.

PUBLISHED JULY 20, 1971' T888,004 MINIMIZING DIFFERENTIAL S H NKAGE 0FMULTILAYER CERAMIC CIRCUIT BOARDS William R. Keller, 3211 Kamerer Drive,Wilmington, Del. 19803 Filed Sept. 1, 1970, Ser. No. 68,757 Int. Cl.B32b 31/26; C04b 39/00 US. Cl. 156-89 No Drawing. 11 Pages SpecificationIn the process for producing multilayer ceramic circuit boardscomprising laminating by firing two or more layers of green ceramictape, wherein one or more surfaces of the layers of tape have electricalcomponents printed thereon and wherein the green ceramic tape shrinksdifferentially in its width or x-axis direction as compared to itslength or y-axis direction when fired, the improvement which comprisesminimizing differential shrinkage of the circuit boards upon firing bystacking the layers of green tape alternately so that each successivelayer has its x-axis direction aligned with the y-axis direction of thepreceding layer. The green ceramic tape comprises finely divided ceramicparticles and an organic binder therefor and is prepared by doctorblading an aqueous or organic dispersion of the ceramic particles andthe binder, followed by eliminating the solvent, e.g., by drying. Afterstacking the layers of green tape in the above-described orien tation,the layers are laminated, e.g., by heat or pressure, and then fired tosinter the ceramic layers and to remove the binder.

